SI9105 Datasheet, PDF (7/7 Pages) Vishay Siliconix – 1-W High-Voltage Switchmode Regulator

Si9105
Vishay Siliconix
DETAILED DESCRIPTION (CONT’D)
SHUTDOWN and RESET
SHUTDOWN and RESET are intended for overriding the
output MOSFET switch via external control logic. The two
inputs are fed through a latch preceding the output switch.
Depending on the logic state of RESET, SHUTDOWN can be
either a latched or unlatched input. The output is off whenever
SHUTDOWN is low. By simultaneously having SHUTDOWN
and RESET low, the latch is set and SHUTDOWN has no effect
until RESET goes high. The truth table for these inputs is given
in Table 1.
Both pins have internal current source pull-ups and can be left
disconnected when not in use. An added feature of the current
sources is the ability to connect a capacitor and an
open-collector driver to the SHUTDOWN pin to provide
variable shutdown time.
Output Switch
The output switch is a 7-W, 200-V lateral DMOS transistor. Like
discrete MOSFETs, the switch contains an intrinsic body-drain
diode. However, the body contact in the Si9105 is connected
internally to −V_IN and is independent of the SOURCE.
Table 1: Truth Table for the SHUTDOWN and RESET Pins
SHUTDOWN
H
H
L
L
RESET
H
H
L
L
Output
Normal Operation
Normal Operation (No Change)
Off (Not Latched)
Off (Latched)
Off (Latched, No Change)
APPLICATIONS
+V_IN
NC
+
20 mF
−
910 k
0.1 mF
NC
2
8
11
3
7
6
Si9105DJ
12
14
10
13
1
0.1
5
mF
0.1
mF
820 k
4
9
15 k
0.22 mF
3.9 W
7
L_p = 3.8 m H
8
1N4148
10
71.5 k
1%
9
12 V
1 mF
47.5 k
1%
1N5819
2
0.1 mF
3
+5 V
220 mF
5.6 V
OUTPUT
0.1 mF
4
1N5819
150 k
47 mF
−5 V
INPUT GND (GND Plane)
FIGURE 5. CCITT Compatible ISDN Terminal Power Supply
Vishay Siliconix maintains worldwide manufacturing capability. Products may be manufactured at one of several qualified locations. Reliability data for Silicon Technology and
Package Reliability represent a composite of all qualified locations. For related documents such as package/tape drawings, part marking, and reliability data, see
http://www.vishay.com/ppg?70003.
Document Number: 70003
S-42030—Rev. H, 15-Nov-04
www.vishay.com
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